I've been using them for almost a year now and very satisfied with it overall. The only important cons are its customer service, which is lousy to say the least, and their still limited selection of phones, although there has been some improvement in this department. I am currently using the LG620G, which I think is a wonderful phone, especially for its price.
Although I normally use the 300 minutes plan, and I've also used the 900 minutes plan, it is good to know that Net 10 offers a wide variety of interchangeable plans, even the 30 day 750 minute plan and the 30 day unlimited plan. As a matter of fact, because my phone usage has increased, I will be trying one of these pretty soon, perhaps the monthly 750 minute plan.
Reception is always good, have not had a dropped call, and adding minutes via internet has been flawless. All things considered, this is an excellent choice for cell phone connection and I do not regret for one moment having made the switch from AT&T.